The objective of my research is an increased understanding of the way nervous systems are organized on the cellular level. I proceed by relating the network properties of a group of neurons to the cellular physiology and molecular biophysics of the synapses which interconnect them. Synaptic neurobiology and interneuronal organization are correlated by examining the buccal ganglia of the mollusk Aplysia californica. This preparation contains a reference population of 26 cells, including 4 multi-action interneurons, which is analyzable at several levels: of the identified individual neuron, of the synaptic connections between individual identified cells, and of the cell networks formed by these identified synapses. Electroanatomical identification of additional neurons, simultaneous intracellular recordings from pre- and post-synaptic elements, voltage-clamping of postsynaptic potentials, and fluctuation spectra of molecular events are techniques used to yield answers to such questions as: How is a neural network anatomically specialized on the cellular level to function as two parallel channels? How are cells specialized to aid co-ordination of bilateral activity? Can a neuron inhibit itself? and Do molecular properties of postsynaptic membrane components determine the time course of conductance changes underlying a CNS postsynaptic potential? The principles of organization of identified cell networks in this preparation may prove generalizeable to experimentally less accessible populations of vertebrate neurons. BIBLIOGRAPHIC REFERENCE: Gardner, D. 1975. A self-inhibitory synaptic potential (SISP) in Aplysia buccal ganglia. Neuroscience Abstracts 1:571.